Conventionally, a connector terminal formed by applying metal plating to a surface of a base material such as copper or copper alloy has been generally used as the one for connecting an electrical component or the like of an automotive vehicle. Tin is most general as such plating metal, but silver is used particularly for terminals for high current in some cases since it provides relatively low contact resistance and good connection reliability.
However, silver is soft metal and aggregation on a surface easily occurs. This causes problems of an increase in coefficient of friction at a contact portion and a reduction in wear resistance and an increase in terminal insertion force associated with that in a silver-plated terminal.
To reduce the coefficient of friction at the terminal contact portion, it is known to form a layer containing organic components on the contact portion and provide a lubrication effect. For example, it is disclosed in patent literature 1 to form an organic substance bonding layer made of an organic compound containing a thiol group on a surface of a plating layer of gold or the like and form a lubricant layer made of oil on the former layer. Further, it is disclosed in patent literature 2 to form a coating film having a thickness of 0.2 to 0.5 μm, in which fluororesin fine particles and fluorine-based oil are mixed, on a substrate surface. In application, fluororesin fine particles and fluorine-based oil are dispersed and diluted in a fluorine-based solvent.